Golf ball and the like



Feb. 15, 1938. H. s. RIDDLE 2,108,321

GOLF BALL AND THE LIKE Filed July 24, 1934 04mm .5411 Smuc rum:

6A6 PROD/ICING mm Aer/144mm Mme/Ms I REM/"W6 CORE INVENTOR 152250 6.3/00 BY TORNEYS Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE 5Claims.

This invention relates to a method of manuiacturing golf balls andsimilar balls in which a hard lively ball is desired.

Golf balls are commonly made by applying a large number of windings ofrubber thread or tape .under tension to a rubber core and thenvulcanizing or otherwise applying a cover of rubher, or other suitablematerial, over the tape or thread windings. It has been proposed toincrease the li'veliness of the ball by adding to the tension of therubber windings the pressure exerted by an inert gas or liquid confinedunder pressure within the core. This has been done in the case of gasesby forming a hollow in the center of the core and placing .thereinsuitable chemlcals which, when subjected to the heat of vulcanization,would combine to form a gas to give,

the desired pressure. If the gas pressure is to be effective it must becreated after the windin operation and the heat generated by the finalvulcanization of the cover has in the past been' utilized to supply theheat necessary to activate the gas forming chemicals at the center ofthe ball. This has proved objectionable since the heat of necessitypasses through the rubber windings to reach the chemicals and theelasticity of the windings is to some extent destroyed. Various attemptsto minimize this dififlcuity have been made as by the use of lowtemperature vulcanization but this results in a slow evolution of thechemicals into gas and. the subjection of the'z'ubber windings to thetransmission of heat for a substantial period. It has also been apractice to inject liquid under pressure into the center of the finishedball by means of a hollow needle. This latter method entails substantiallabor and expensive equipment and involves a damage to the windings bythe passage of the needle and uncertainty in the complete closure of theaperturemade by the needle.

It is the principal object of my invention to provide a method by whichpressure may be created at the center of a golf ball after the ball hasotherwise been completely finished without passing heat throughthe'windings or mutilating the windings by the insertion of a needle,and witha substantial decrease in equipment and labor costs and asubstantial saving in time. Other and further objects will be apparentfrom the following specification and claims.

The accompanying drawing illustrates diagrammatically one mannerofpracticing the invention, the ball being indicated in section.

In carrying out my invention, suitable predetermined quantities of gasproducing chemicals or materials are placed in the core cavity of theball accompanied by a small piece of metal such as tin-foil or the likeand the manufacture of the ball completed in the usual or any suitablemanner. By "completed is meant that degree of structural completiondesired and at which the increased'pressure should be added to providethe best performance of the ball in its intended use. Usually this willbe after the windings have been applied but may-be prior to or after theapplication of the cover, and before or after painting or otherwisefinishing thesurface. I then pass the completed ball into or through thefield of a high frequency coil as indicated in broken line in thedrawing. The metal foil is preferably very thin and the piece may bebent into angular form to give added assurance that a metal surface isproperly positioned in the field. The action of the high frequency held,as that term is used, is to induce a current in the metal and raise itstemperature to a point suificient to activate the chemicals or causecombustion of the material associated with the metal in the core cavity.Depending on the chemicals or ma terials used and the size and intensityof the held, the ball may be held for a longer or shorter period in thefield or, with semi-explosive, explosive or detonating materials, theballs may be passed continuously through the field. The gas producingchemicals heretofore usually used, such as ammonium nitrate or a mixtureof ammonium chloride and sodium nitrate, may be usedin the practice ofmy method but one of the advantages of the method is that it permits theuse of many classes of materials heretofore impossible of such use,which are quicker in action and involve a, minimum production of heat.For example, gun powder and many other semiexplosive or explosivematerials, similar nitrogen producing compounds, or materials in whichthe reaction once started is self sustaining, capable of producing asufiicient volume of substantially inert gas and ignitable or reactingonly at sufficiently high temperatures to preclude activation within therange of temperatures involved in the manufacture of the ball, may beused. As illustrating the small quantities of materials required,assuming a core cavity 7 mm. in diameter, and that it is desired tocreate a pressure of 1200 lbs. per square inch within the core, thedesired pressure could be obtained with approximately .064 gram of blackpowder, using a piece of thin tin-foil presenting an effective areaabout A" square.

Whatever type of gas producing chemical or frequency field, and theincidental heat produced may be largely or entirely dissipated in thecore or central portion of the ball.

The method permits a wide range of choice to the manufacturer in meetingtechnical requirements or specific factory conditions. For example, if'to meet safety regulations or fire underwriters requirements, it isdesirable or necessary in a particular instance to use relatively slowacting or high heat producing materials, refrigeration may be used tomaintain the outer portion of the ball, including the windings, at apredetermined temperature during the time the ball is within the highfrequency field without impairing the action produced at the center. Asimilar result in a degree can be obtained by providing a layer of heatinsulating material between the core and the windings.

The method further permits incidental refinementand improvement of theproduct. For example, the cover may be compounded to vulcanize at verylow temperatures or even be air cured, or the elasticity lost byvulcanizing the cover at a high temperature may be compensated byproducing an increased pressure at the center. Again, since it is nolonger necessary to conduct heat through the ball to the core cavity,the core may be compounded and cured so as to minimize dispersion of gasinto the ball structure.

Further, since the method permits the selection of gas producingmaterials which require the use of exceedingly small quantities, thecore cavity need be no larger than necessary to accommodate the gasforming material and the required area of tin-foil or other metal. Onthe other hand, the cavity may be as large as desired. The materialsused may partly or completely fill the cavity and may be powdered,liquid, gelatinous, or in semi-solid or solid form to facilitate uniformwinding by preventing any tendency of the core to collapse or deformunder the winding pressure. The gas forming material may be molded inspherical form with the metal inside, and itself form the ball core orthe major portion thereof, being covered with a gas retaining coveringof rubber or other suitable material by dipping, molding, or in anyother suitable manner;

The apparatus required may be exceedingly simple and in its simplestform may comprise any suitable means for creating a high frequency fieldsuch as a conventional high frequency coil of small copper tubingthrough which a flow of cooling water is maintained and carrying analternating current having for example a frequency of 300 k0,, the powerconsumption being about 1 or 2 kw., together with suitable means forpassing the balls successively into or through the field of the coil inthe desired timed relation.

It will be understood that the above discussion is intended to indicategenerally the wide range of operating detail and construction madepossible by my method and is not to be taken as narrowly definitive ofthe scope of my invention.

What I claim is:

1. The method of manufacturing golf balls and the like which comprisesenclosing within the center of the ball a quantity of a gas producingmaterial in company with a piece of metal, completing the ball structureas desired and inducing in said piece of metal an electric current ofsufficient intensity to activate the gas producing material.

2. The method of manufacturing golf balls and the like which comprisesenclosing within the center portion of the ball a gas producing materialin company with a piece of metal bent in angular formation, completingthe ball structure as desired and inducing in said piece of metal anelectric current of sufiicient intensity to activate the gas producingmaterial.

3. The method of manufacturing golf balls and the like which comprisesenclosing within the center portion of the ball a quantity of gasproducing material, completing the ball structure as desired andactivating the gas producing material by the generation of heat at thecenter portion of the ball without raising the temperature of the otherportions of the ball substantially above their normal tolerance.

4. The method of manufacturing golf balls and the like which comprisesenclosing within the center portion of the ball a quantity of materialgasifying above a predetermined temperature, completing the ball as.desired, and raising the center portion of the ball to saidpredetermined temperature by the generation of heat at said centerportion without deleteriously heating the other portions of the ball.

5. The method of manufacturing golf balls and the like which comprisesenclosing within the center portion of the ball'a quantity of gasproducing material in association with an electric conductive materialand inducing in said material an electric current suficient to activatethe gas producing material.

HERBERT S. RIDDLE.

